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根据封丘县土壤发生学特点遴选质地、有机质、土壤颜色、pH值、电导率和土壤发生层厚度等作为土壤属性向量,运用k-均值算法模型,对研究区40个土壤剖面样本实施数值化分类,并依据《中国土壤系统分类检索》确定算法模型输出的5个中心土壤剖面的系统分类归属。基于40个样本土壤剖面剖面与各中心剖面类型之间的分类距离,应用地统计学手段预测研究区空间任意位置的土壤与各中心剖面分类距离,完成研究区土壤数值化连续分类并在空间上实现可视化表达。在此基础上,运用去模糊化手段,“硬化”连续分类边界,获得可与传统土壤制图互为参比的研究区土壤预测制图,并对输出结果进行了土壤发生学解释。本研究表明,土壤数值化分类手段与地统计学随机模型相结合可以实现区域土壤的空间预测,且预测制图比传统土壤制图蕴含更加丰富的信息。 相似文献
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遗传标记经历了形态标记、细胞学标记、生化标记和分子标记等4个阶段,其中分子标记的发展最为迅猛和有效。本文比较了几种主要分子标记方法的特点,为更好地利用分子标记提供了理论依据,并对分子标记在林木遗传多样性研究、遗传育种、DNA指纹图谱的构建、亲缘关系鉴定及分类研究等方面的应用做了介绍。 相似文献
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现生鼢鼠是分布于东亚的一类典型地下啮齿动物,中国西部是其多个种的模式产地和主要分布区域。该类动物分布广、数量多,经济和生态意义重要,有关其控制和管理问题长期存有困扰。有效的物种管理离不开分类及生态学知识,但学界对该类群的分类地位与系统发育关系等至今仍有争议。随着分子系统学等现代科学技术的发展,其系统发育和分类地位等产生了许多新的研究结果。本文对近年来鼢鼠现存种系统学方面取得的研究进展进行了梳理,综述了鼢鼠亚科动物各系统分类的观点及其主要依据,分析了一些存在的问题,并就如何进一步分类研究等提出了建议,旨在促进鼢鼠亚科动物系统分类学研究的发展,为该类群物种资源合理利用与管理等提供基础资料。 相似文献
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《生物化学与生物物理进展》2012,(11):1128
分子系统发生学书号:978-7-03-033026-0/Q.2820作者:黄原定价:$120分子系统发生学是应用分子数据重建系统发生关系的学科.本书全面系统地论述了分子系统发生学的基础、原理、方法及应用.分子系统发生学是当前生命科学的一个热点领域,本书是作者20余年来在系统发生学领域研究和教学的 相似文献
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系统发生学是研究生物类群间进化关系的学科。随着测序技术、分析方法和计算能力的改进,分子数据被广泛应用,促进了系统发生学的快速发展。系统发生树已成为生态学和比较生物学等研究领域的有力工具。然而,许多研究在进行系统发生树构建时更侧重各种软件的使用,一些基本原则或注意事项有时会被弱化甚至忽视。该文详细介绍了基于分子数据进行系统发生树构建的工作流程和基本方法,包括类群取样、分子标记选择、序列比对、分区及模型选择、序列联合分析以及拓扑结构检验等关键步骤。此外,该文还为系统发生树构建常用的3种方法(最大简约法、最大似然法和贝叶斯法)提供了相应的软件操作流程和运行命令,以期为相关研究提供参考。 相似文献
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A review of the bladed Bangiales (Rhodophyta) in China: history,culture and taxonomy 总被引:1,自引:0,他引:1
In this paper, we review cultural history, mariculture and taxonomic work to date for Porphyra sensu lato (bladed Bangiales) in China. The bladed Bangiales are a red seaweed group with high species biodiversity and economic value. In China, species occur along the length of the coast and are highly integrated into the country’s culture. Chinese people have used the bladed Bangiales as food and pharmaceuticals for about 1700 years with many references to these seaweeds in ancient books. The mariculture of bladed Bangiales in China also has a long history and an industry has been established based on some species, notably Pyropia yezoensis. The scientific study of the taxonomy of the bladed Bangiales in China began in the late 1920s and to date, based on morphological identification, 25 species and five varieties have been recorded for China, of which 12 species are considered to be endemic to the country. The majority of species have distribution data showing evidence of possible changes due to increasing water temperatures along the coast. The global biodiversity of the bladed Bangiales has been revealed using molecular approaches. This points to the need for molecular taxonomy of Chinese material to document species diversity and distribution, particularly as it includes the wild stocks for seaweed cultivation and because coastal habitats are increasingly impacted by the increasing human population and an expanding mariculture industry. There is a considerable body of literature on the bladed Bangiales in China, but much of it is Chinese and in obscure publications, so we review it here for the benefit of readers worldwide. 相似文献
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DNA barcoding is a promising tool for the rapid and unambiguous identification of species. Some arcoid species are particularly difficult to distinguish with traditional morphological identification owing to phenotypic variation and the existence of closely related taxa. Here, we apply DNA barcoding based on mitochondrial cytochrome c oxidase I gene (COI) to arcoid species collected from the coast along China. Combining morphology with molecular data indicates the 133 specimens of Arcoida could be assigned to 24 species. Because of the deep genetic divergence within Tegillarca granosa, there was an overlap between genetic variation within species and variation between species. Nevertheless, NJ and Bayesian trees showed that all species fell into reciprocally monophyletic clades with high bootstrap values. Our results evidence that the COI marker can efficiently identify species, correct mistakes caused by morphological identification and reveal genetic differentiation among populations within species. This study provides a clear example of the usefulness of barcoding for arcoid identification. Furthermore, it also lays a foundation for other biological and ecological studies of Arcoida. 相似文献
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控制水稻胚乳淀粉合成代谢若干关键酶基因对花后高温的响应表达 总被引:1,自引:0,他引:1
以稻米品质温度敏感型的早籼稻品种嘉早935为材料,利用人工气候箱控温试验和实时荧光定量PCR技术,探讨了不同灌浆温度(日均温分别为22和32 ℃)处理下胚乳淀粉分支酶(SBE)、淀粉去分支酶(DBE)和淀粉合酶(SS)的10个同工型基因(sbe1、sbe3、sbe4、pul、isa1、isa2、isa3、Wx、sss1和sss2a)的相对表达量差异及动态变化特征.结果表明: 淀粉合成相关功能基因对水稻灌浆期高温胁迫的响应表达方式存在明显差异,而且因同工型的类型而不同.在高温处理下,sbe1和sbe3的相对表达量显著下降,二者属于SBE类基因中对高温胁迫较敏感的主要同工型;DBE基因中,pul属于高表达的同工型,而且其对高温胁迫响应比isa1、isa2和isa3敏感;在Wx、sss1和sss2a中,sss2a的相对表达量显著低于sss1和Wx, 但sss2a和sss1对高温胁迫响应比Wx敏感,因此二者可能也是高温胁迫对胚乳淀粉结构进行调控的重要位点,尤其在水稻灌浆的中后期发挥重要作用. 相似文献
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Woo-Jin Kim Sudath T. Dammannagoda Hyungtaek Jung Il Seon Baek Ho Seop Yoon Sang Duk Choi 《Genes & genomics.》2014,36(5):611-624
The native Asian oyster, Crassostrea ariakensis is one of the most common and important Crassostrea species that occur naturally along the coast of East Asia. Molecular species diagnosis is a prerequisite for population genetic analysis of wild oyster populations because oyster species cannot be discriminated reliably using external morphological characters alone due to character ambiguity. To date there have been few phylogeographic studies of natural edible oyster populations in East Asia, in particular this is true of the common species in Korea C. ariakensis. We therefore assessed the levels and patterns of molecular genetic variation in East Asian wild populations of C. ariakensis from Korea, Japan, and China using DNA sequence analysis of five concatenated mtDNA regions namely; 16S rRNA, cytochrome oxidase I, cytochrome oxidase II, cytochrome oxidase III, and cytochrome b. Two divergent C. ariakensis clades were identified between southern China and remaining sites from the northern region. In addition, hierarchical AMOVA and pairwise Φ ST analyses showed that genetic diversity was discontinuous among wild populations of C. ariakensis in East Asia. Biogeographical and historical sea level changes are discussed as potential factors that may have influenced the genetic heterogeneity of wild C. ariakensis stocks across this region. 相似文献
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Anna-Lisa Wrange Johanna Valero Lisbeth S. Harkestad Øivind Strand Susanne Lindegarth Helle Torp Christensen Per Dolmer Per Sand Kristensen Stein Mortensen 《Biological invasions》2010,12(6):1453-1458
The Pacific oyster (Crassostrea gigas) is an important aquaculture species world-wide. Due to its wide environmental tolerance and high growth rate, it has also become a successful invader in many areas, leading to major ecosystem changes. Low water temperatures were previously believed to restrict the establishment of Pacific oysters in Scandinavia. However, recent surveys reveal that the Pacific oyster is now established in many areas in Scandinavia. The biomass of oysters in the Danish Wadden Sea has increased dramatically between 2005 and 2007, large numbers were observed along the Swedish west coast from settlement in 2006, and in Norway, populations are established along the southwest coast to 60°N. 相似文献
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红树植物多样性及其研究进展 总被引:8,自引:0,他引:8
红树植物是分布于热带、亚热带海岸潮间的木本植物群落。因因适应海岸带和作的生长环境形成了独特的形态结构和生理生态特性。红树林是海岸有重要价值的湿地。论述了红树植物的物 多样性、适应多样性、物侯多样性以及分子水平的多样性及其研究进展。 相似文献
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We carried out a two-part investigation that revealed habitat differences in marine invertebrate invasions. First, we compared
invasion levels of hard vs soft substrata in Elkhorn Slough, an estuary in Central California, by comparing abundance and
richness of native vs exotic species in quantitative samples from each habitat type. Our results revealed that the hard substrata
were much more heavily invaded than the soft substrata. Nearly all the hard substrata in Elkhorn Slough, as in most estuaries
along the Pacific coast of North America, are artificial (jetties, rip-rap, docks). Some exotic species may by chance be better
adapted to this novel habitat type than are natives. Two major vectors responsible for marine introductions, oyster culturing
and ship-hull fouling, are also more likely to transport species associated with hard vs soft substrata. Secondly, we compared
estuarine and open coast invasion rates. We examined species richness in Elkhorn Slough and adjacent rocky intertidal habitats
along the Central California coast. The absolute number of exotic species in the estuary was an order of magnitude higher
than along the open coast (58 vs 8 species), as was the percentage of the invertebrate fauna that was exotic (11% vs 1%).
Estuaries on this coast are geologically young, heavily altered by humans, and subject to numerous transport vectors bringing
invasive propagules: all these factors may explain why they are strikingly more invaded than the open coast. The finding that
the more species rich habitat – the open coast – is less invaded is in contrast to many terrestrial examples, where native
and exotic species richness appear to be positively correlated at a broad geographic scale. 相似文献
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Identifying the true oysters (Bivalvia: Ostreidae) with mitochondrial phylogeny and distance-based DNA barcoding 总被引:1,自引:0,他引:1
Oysters (family Ostreidae), with high levels of phenotypic plasticity and wide geographic distribution, are a challenging group for taxonomists and phylogenetics. As a useful tool for molecular species identification, DNA barcoding might offer significant potential for oyster identification and taxonomy. This study used two mitochondrial fragments, cytochrome c oxidase I (COI) and the large ribosomal subunit (16S rDNA), to assess whether oyster species could be identified by phylogeny and distance-based DNA barcoding techniques. Relationships among species were estimated by the phylogenetic analyses of both genes, and then pairwise inter- and intraspecific genetic divergences were assessed. Species forming well-differentiated clades in the molecular phylogenies were identical for both genes even when the closely related species were included. Intraspecific variability of 16S rDNA overlapped with interspecific divergence. However, average intra- and interspecific genetic divergences for COI were 0-1.4% (maximum 2.2%) and 2.6-32.2% (minimum 2.2%), respectively, indicating the existence of a barcoding gap. These results confirm the efficacy of species identification in oysters via DNA barcodes and phylogenetic analysis. 相似文献
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Carrasco N Villalba A Andree KB Engelsma MY Lacuesta B Ramilo A Gairín I Furones MD 《Journal of invertebrate pathology》2012,110(3):307-313
Bonamia exitiosa and Bonamia ostreae are parasites that reproduce within the haemocytes of several oyster species. In Europe, the host species is the flat oyster Ostrea edulis. The parasite B. ostreae has been responsible for mortalities since the late 1970s throughout the European Atlantic coast. B. exitiosa was first detected, in 2007, on this continent in flat oysters cultured in Galicia (NW Spain). Since then, the parasite has also been detected in France, Italy and the United Kingdom. The bays of the Ebro Delta in the south of Catalonia represent the main bivalve culture area in the Mediterranean coast of Spain. Previous information from the area includes reports of several flat oyster pathogens, including the notifiable parasite Marteilia refringens. However, the status with regard to Bonamia parasites was uncertain. In the present study, a Bonamia parasite was observed in flat oysters cultured in the Alfacs Bay of the Ebro Delta by histology and real-time PCR. PCR-RFLP and sequencing suggested the presence of B. exitiosa. Finally, phylogenetic analyses of the studied Bonamia isolates corroborated B. exitiosa infection. M. refringens was also observed in the same oyster batch, and co-infection with both parasites was also detected. This is the first detection of B. exitiosa, in Catalonia and the Spanish Mediterranean coast. The impact of the parasite on the Mediterranean flat oyster activity needs to be urgently addressed. 相似文献